This commit improves SimpleAliasRegistryTests in the following ways.
- Some existing methods have been split up into smaller test methods
which focus on a single use case.
- The use of Mockito mocks has been replaced by a hand-crafted
StubStringValueResolver which ensures that existing aliases and names
are not accidentally replaced by null thereby removing their removing
there mappings inadvertently.
- Several test methods now include inline comments that document the
current state of the aliasMap in order to clarify what is happening
behind the scenes in the ConcurrentHashMap.
- Several test methods warn that the current expectations are based on
ConcurrentHashMap iteration order!
- New @ParameterizedTest which is currently @Disabled but
demonstrates that complex use cases involving placeholder replacement
can be supported consistently -- regardless of the values of the
aliases involved -- but only if alias registration order is honored.
Closes gh-31353